a) Field of the Invention
The invention relates to an endoscope for laser lithotripsy having a light guide connectable proximally to a laser light-source, which guide passes through a passage in the endoscope and can have its distal end lined up under visual control with the concretion to be destroyed by using the telescope of the endoscope.
b) Description of the Prior Art
Endoscopes combinable with laser devices for performing different tasks form a known and commercially available part of medical technology. The prior art includes instruments of this kind which can be employed as surgical scalpels or by means of which bleeding for example can be stopped by coagulation or diseased parts of organs can be selectively bombarded with light. For this purpose the endoscopes generally have insertion passages through which the laser devices can be passed, so that not only is it possible to perform treatments of the kinds which are listed above by way of illustration but also the area of operation can be monitored visually during the treatment process.
As an example, reference may be made to DE-OS 29 45 080 (see U.S. Pat. No. 4,313,431) which relates to an instrument for endoscopic laser irradiation for treating tumours of the bladder. In this instrument, use is made of a tube which encloses a further tube to receive the endoscope plus additional passages which serve to receive or guide, as the case may be, irrigation liquid, a fiber light guide and thrust-rod linkage for aligning the distal end region of the fiber light guide. By means of the thrust-rod linkage the distal end of the light guide can be swivelled off the axis of the instrument and in this way the laser beam can be positioned precisely on the treatment site. Provision is also made for the fiber light guide to be longitudinally displaceable.
Combined with the alignability described above, the purpose of the provisions described is to enable any dirt or fouling on the distal end of the light guide to be removed by moving the distal end forward into the liquid in the bladder and swivelling it from side to side in this position. If the distal end region is dirty, the aim is to avoid having to withdraw it from the patient's body to clean it and then having to re-insert it. Finally, reference will be made to the instrument disclosed in U.S. patent specification No. 3865113 which can be used as a surgical scalpel. In this case too the cutting function is performed by a laser beam, which beam travels through a tubular handpiece and is focussed onto a focussing point by a lens. To allow the instrument to be put into operation, the handpiece is provided with attachments which can be fitted onto it and each of which is adapted to a particular task and forms a guiding element which makes it possible for the surgeon to guide the focussing point in a suitable way for him to perform the operation properly.
In laser lithotripsy, a high-energy laser beam is conveyed to the concretion to be destroyed, this generally being done via a light guide forming part of an endoscopic instrument which is brought up to the concretion in question by being inserted in the relevant body cavity. When this is done, there is a risk of the distal end of the light guide coming into contact with the conretion to be destroyed, which could result in damage to the delicate part in question. It is also important that the transmission of the energy to the concretion should take place repeatably and in an optimum fashion, which makes it necessary for the distance between the distal end of the light guide and the concretion intended for destruction to be accurately adjustable.
The main object of the invention is therefore to design an endoscope of the kind described above in such a way that the requirements mentioned can be met.